Scanning lidar with a coupled radar safety system

A small scanning three-wavelength lidar system at NASA Langley Research Center in Hampton, Virginia, has been used since 1992 to make atmospheric measurements on stratospheric and upper tropospheric aerosols and on the evolution of aircraft exhaust plumes. Many of these measurements have been made away from the zenith, and, to reduce the hazard to air traffic produced by the laser beam, a radar safety device has been installed. The radar application is original in that the radar beam is made collinear with the laser beam by use of a dichroic mirror that transmits the laser radiation and reflects the microwaves. This mirror is inserted into the outgoing optical path prior to the radiation from both the radar and the laser passing through the independent scanning unit. Tests of the complete system show that the lidar and radar beams remain collocated as they are scanned and that the radar can be used to inhibit the laser prior to an aircraft passing through the beam.     

Assessing genomic prediction accuracy for Holstein sires using bootstrap aggregation sampling and leave-one-out cross validation

Since the introduction of genome-enabled prediction for dairy cattle in 2009, genomic selection has markedly changed many aspects of the dairy genetics industry and enhanced the rate of response to selection for most economically important traits. Young dairy bulls are genotyped to obtain their genomic predicted transmitting ability (GPTA) and reliability (REL) values. These GPTA are a main factor in most purchasing, marketing, and culling decisions until bulls reach 5 yr of age and their milk-recorded offspring become available. At that time, daughter yield deviations (DYD) can be compared with the GPTA computed several years earlier. For most bulls, the DYD align well with the initial predictions. However, for some bulls, the difference between DYD and corresponding GPTA is quite large, and published REL are of limited value in identifying such bulls. A method of bootstrap aggregation sampling (bagging) using genomic BLUP (GBLUP) was applied to predict the GPTA of 2,963, 2,963, and 2,803 young Holstein bulls for protein yield, somatic cell score, and daughter pregnancy rate (DPR), respectively. For each trait, 50 bootstrap samples from a reference population comprising 2011 DYD of 8,610, 8,405, and 7,945 older Holstein bulls were used. Leave-one-out cross validation was also performed to assess prediction accuracy when removing specific bulls from the reference population. The main objectives of this study were (1) to assess the extent to which current REL values and alternative measures of variability, such as the bootstrap standard deviation (SD) of predictions, could detect bulls whose daughter performance deviates significantly from early genomic predictions, and (2) to identify factors associated with the reference population that inform about inaccurate genomic predictions. The SD of bootstrap predictions was a mildly useful metric for identifying bulls whose future daughter performance may deviate significantly from early GPTA for protein and DPR. Leave-one-out cross validation allowed us to identify groups of reference population bulls that were influential on other reference population bulls for protein yield and observe their effects on predictions of testing set bulls, as a whole and individually.     

The effects of cereal additives in low-fat sausages and meatballs. Part 1: Untreated and enzyme-treated rye bran

Rye bran was added to frankfurter-type sausages and meatballs with the aim of producing low-fat products with increased dietary fibre content. The addition of untreated rye bran to sausages was detrimental, causing a substantial increase in frying loss (20% compared to 13.2%). The addition of rye bran treated with hydrolytic enzymes reduced the frying loss to 15.2–16.4%. The firmness was also improved by the treatments (12.8–14.2 N compared to 8.8 N). Enzymatic treatment of rye bran did not however improve the water-holding capacity or the texture of sausages compared to the rye bran that had only been soaked in water. The reason could be that enzymes degraded the solubilized fraction of the dietary fibre, leaving small fragments that cannot contribute to the water-holding capacity and the texture of the sausages. The benefits of treating rye bran in water were not seen in meatballs, probably due to the more particulate structure of meatballs, which is not as sensitive to additives.     

Mechanical Properties of an Fe‐Based SAM2×5‐630 Metallic Glass Matrix Composite with Tungsten Particle Additions

We present the role of tungsten additions on the mechanical properties of a Fe‐based structural amorphous metal (SAM2×5‐630) containing crystalline tungsten. Matrix cracking by microindentation is inhibited by the addition of tungsten and indicates that tungsten improves the fracture toughness. Response surfaces from nanoindentation arrays indicate that the hardness and modulus of the matrix phase are increased by tungsten additions. Bulk composites with 30 vol% tungsten subjected to 4‐point flexure exhibited brittle fracture behavior and the characteristic strength and Weibull modulus were 165 and 8.7 MPa, respectively. The addition of tungsten did not cause devitrification of the matrix phase.     

The sulphidation of alloys used in a fluidized bed combustor

The results of an investigation of the sulphidation behaviour of lncoloy BOOH and AISI 310 stainless steel in coal combustion conditions at temperatures between 650°C and 900°C are presented. Laboratory tests were carried out in controlled environments in the presence of solids representative of fluidized bed combustor operation. The morphology and composition of scale formed during sulphidation was examined and compared with that from tube samples removed from test rigs operated by the National Coal Board. The results have shown that at 900°C a gas mixture corresponding to the equilibrium conditions close to the coexistence point for CaS0₄, CaO and CaS on the phase stability diagram is sufficient to induce sulphidation. However, at lower temperatures an interaction between the deposit and the protective oxide is necessary and in some cases the presence of typical contaminants found in coals is an added requirement. The morphology of the corrosion products found in practice can be reproduced under controlled conditions in laboratory tests. The results are interpreted in terms of likely mechanisms of the processes involved.     

Localization of trehalose in partially hydrated DOPC bilayers: insights into cryoprotective mechanisms

Trehalose, a natural disaccharide with bioprotective properties, is widely recognized for its ability to preserve biological membranes during freezing and dehydration events. Despite debate over the molecular mechanisms by which this is achieved, and that different mechanisms imply quite different distributions of trehalose molecules with respect to the bilayer, there are no direct experimental data describing the location of trehalose within lipid bilayer membrane systems during dehydration. Here, we use neutron membrane diffraction to conclusively show that the trehalose distribution in a dioleoylphosphatidylcholine (DOPC) system follows a Gaussian profile centred in the water layer between bilayers. The absence of any preference for localizing near the lipid headgroups of the bilayers indicates that the bioprotective effects of trehalose at physiologically relevant concentrations are the result of non-specific mechanisms that do not rely on direct interactions with the lipid headgroups.     

Detection of Non-metallic Inclusions in Steel Continuous Casting Billets

This work applied automated particle analysis to study non-metallic inclusions in steel. Compared with traditional methods, the approach has the advantage of capturing the morphology, measuring the size, recording the original positions, and identifying the composition of inclusions on a selected area in a short time. The morphology and composition of typical inclusions were analyzed using partial acid extraction and discussed through thermodynamic calculation. Steel samples were collected from the entire cross section of billets cast during times of steady state and ladle change. The spatial distribution of inclusions agreed well with the measurement of the total oxygen. The spatial distribution of inclusions was plotted to represent the entrapment positions of inclusions on the casting strand and their concentration on the cross section of the billet. Also, regarding the different size and type of inclusions, the spatial distribution of classified inclusions was explored such as the distribution of sulfide, oxide, and high sodium and potassium content inclusions. The sufficient information could be used to identify the source of inclusions and guide the steel refining process.